$62 



THE POPULAR SCIENCE MONTHLY. 



more or less magnified, and is to be distin- 

 guished from micro photography, which 

 merely takes microscopic photographs of 

 objects that can be seen by the naked eye. 

 The former art is scientifically instructive, 

 the latter merely produces curiosities. The 

 author's object in preparing the volume has 

 been to give such an account of the tech- 

 nique of the art as will enable persons famil- 

 iar with the use of the microscope to make 

 photo-micrographs of suitable objects with 

 a minimum expenditure of time and money. 

 The illustrations have been selected with a 

 view of showing the kinds of microscopic 

 objects best suited for photographing, and 

 the results which may be expected by one 

 who is willing to devote a little time to the 

 mastering of technical difficulties. They 

 represent forty-nine different objects. 



Sewer-Gas and its Alleged Causation of 

 Typhoid Fever. By George Hamilton, 

 M. D. Pp. 12. The Status of Pro 

 fessional Opinion and Popular Senti- 

 ment regarding Sewer-Gas and Con- 

 taminated Water as Causes of Typhoid 

 Fever. By George Hamilton, M. D. 

 Philadelphia. Pp. 10. Etiology and 

 Non-Infection of Sewer-Gases. By 

 Washington Ayer, M. D., of San Fran- 

 cisco. Pp. 25. 



Dr. Hamilton undertakes to controvert 

 the sewer-gas theory of the origin of ty- 

 phoid fever, by showing that the disease 

 is not dependent upon the presence or ab- 

 sence of sewers, or upon any conditions of 

 filth in large cities ; and that it prevails in 

 the country, where there are no sewers, and 

 everything is favorable to purity of the at- 

 mosphere, more extensively and more fatal- 

 ly than anywhere else. Dr. Ayer maintains 

 substantially the same points, but rather 

 on philosophical grounds than by the cita- 

 tion of examples, and disputes the compe- 

 tency of the experiments which have been 

 relied upon to determine that bacteria are 

 the cause of the diseases with which they 

 have been found associated. 



The Influence of Athletic Games upon 

 Greek Art. By Charles Waldstein, 

 Esq., University of Cambridge, England. 

 Pp. 24. 



This paper is an inquiry into the cause 



of the persistency of the influence of Greek 



art upon us. The answer is found in the 



fact that Greek art is true to nature, yet 



not so servile as to be sensual and sensa- 

 tional, but is also ideal. " The ideal in art 

 is the highest generalization of form. In 

 Greek art it was the highest generalization 

 of the forms of nature. The works of 

 Greek art are, therefore, not dependent for 

 appreciation upon one individual spectator, 

 or one special mood of the individual, but 

 are valid for all sane men, for all men of a 

 certain physiological constitution of their 

 senses, surrounded by man and nature rela- 

 tively the same." The inquiry is pursued 

 how Greek art effected this combination of 

 the natural and the ideal. The natural was 

 developed in the portraiture of athletes, 

 the ideal in the effort to represent and char- 

 acterize the gods. 



An Index to Articles relating to His- 

 tory, Biography, Literature, Society, 

 and Travel, contained in Collections 

 of Essays, etc. By W. M. Griswold, 

 Bangor, Me. Q. P. Index. Pp. 56. 



This is No. 13 of the " Q. P. Index," a 

 series of works for the projection and exe- 

 cution of which Mr. Griswold, who has 

 made it his special business, deserves the 

 thanks of every student and reader. The 

 character of the present number of the 

 series is fairly well represented by its title. 

 There are hosts of articles of great value 

 on particular subjects inclosed in volumes 

 of essays and miscellaneous writings, which 

 arc practically inaccessible because the gen- 

 eral title of the volume gives no clew to 

 what is in it. The present index gives the 

 key to the subjects within its scope as rep- 

 resented in 799 volumes by different au- 

 thors. The publisher hopes in time to im- 

 prove upon it and enlarge it that is, to 

 bring other books into view. 



A Physician's Sermon to Young Men. 

 By William Pratt. New York : M. L. 

 Holbrook & Co. Pp. 48. 25 cts. 



A lecture to young men on the impor- 

 tance of personal purity and of the restraint 

 of all tendencies to vicious indulgence, the 

 destructive physical and moral consequences 

 of which are pointed out in language that 

 does not err by lack of plainness or vigor. 

 As counteractives to vicious propensities, 

 are recommended cold bathing, hard beds, 

 and sleeping alone, abundant work, plain 

 food, careful reading, right choice of com- 

 panions, and religion. 



